Head east towards the Dalles, and there are two different ways to get there. Personally, cross over to the Washington side and then head UP the Klickitat river through the town itself.

Or else, to hit it further upriver, which is always where I access it, go to the town of Goldendale, WA and turn west by the Dairy Queen. Basically, stay on that road for about 15 miles and you'll eventually get to the river. Whatever you do, do NOT merge to the right.

If you need better directions, let me know.